Metal plating compositions

ABSTRACT

Reaction products of primary and secondary diamines and bisanhydrides are included as additives in metal electroplating baths. The metal electroplating baths have good throwing power and deposit metal layers having substantially planar surfaces. The metal plating baths may be used to deposit metal on substrates with surface features such as through-holes and vias.

The present application is a divisional application of co-pendingapplication Ser. No. 15/559,542, filed Sep. 19, 2017.

FIELD OF THE INVENTION

The present invention is directed to reaction products of bisanhydridesand diamines as additives for electroplating baths. More specifically,the present invention is directed to reaction products of bisanhydridesand diamines as additives for electroplating baths to provideelectroplating baths which have good throwing power.

BACKGROUND OF THE INVENTION

Methods for electroplating articles with metal coatings generallyinvolve passing a current between two electrodes in a plating solutionwhere one of the electrodes is the article to be plated. A typical acidcopper plating solution includes dissolved copper, usually coppersulfate, an acid electrolyte such as sulfuric acid in an amountsufficient to impart conductivity to the bath, a source of halide, andproprietary additives to improve the uniformity of the plating and thequality of the metal deposit. Such additives include levelers,accelerators and suppressors, among others.

Electrolytic copper plating solutions are used in a variety ofindustrial applications, such as decorative and anticorrosion coatings,as well as in the electronics industry, particularly for the fabricationof printed circuit boards and semiconductors. For circuit boardfabrication, typically, copper is electroplated over selected portionsof the surface of a printed circuit board, into blind vias and trenchesand on the walls of through-holes passing between the surfaces of thecircuit board base material. The exposed surfaces of blind vias,trenches and through-holes, i.e. the walls and the floor, are first madeconductive, such as by electroless metal plating, before copper iselectroplated on surfaces of these apertures. Plated through-holesprovide a conductive pathway from one board surface to the other. Viasand trenches provide conductive pathways between circuit board innerlayers. For semiconductor fabrication, copper is electroplated over asurface of a wafer containing a variety of features such as vias,trenches or combinations thereof. The vias and trenches are metallizedto provide conductivity between various layers of the semiconductordevice.

It is well known in certain areas of plating, such as in electroplatingof printed circuit boards (“PCBs”), that the use of levelers in theelectroplating bath can be crucial in achieving a uniform metal depositon a substrate surface. Electroplating a substrate having irregulartopography can pose difficulties. During electroplating a voltage droptypically occurs within apertures in a surface which can result in anuneven metal deposit between the surface and the apertures.Electroplating irregularities are exacerbated where the voltage drop isrelatively extreme, that is, where the apertures are narrow and tall.Consequently, a metal layer of substantially uniform thickness isfrequently a challenging step in the manufacture of electronic devices.Leveling agents are often used in copper plating baths to providesubstantially uniform, or level, copper layers in electronic devices.

The trend of portability combined with increased functionality ofelectronic devices has driven the miniaturization of PCBs. Conventionalmultilayer PCBs with through-hole interconnects are not always apractical solution. Alternative approaches for high densityinterconnects have been developed, such as sequential build uptechnologies, which utilize blind vias. One of the objectives inprocesses that use blind vias is the maximizing of via filling whileminimizing thickness variation in the copper deposit between the viasand the substrate surface. This is particularly challenging when the PCBcontains both through-holes and blind vias.

Leveling agents are used in copper plating baths to level the depositacross the substrate surface and to improve the throwing power of theelectroplating bath. Throwing power is defined as the ratio of thethrough-hole center copper deposit thickness to the copper thickness atthe surface. Newer PCBs are being manufactured that contain boththrough-holes and blind vias. Current bath additives, in particularcurrent leveling agents, do not always provide level copper depositsbetween the substrate surface and filled through-holes and blind vias.Via fill is characterized by the difference in height between the copperin the filled via and the surface. Accordingly, there remains a need inthe art for leveling agents for use in metal electroplating baths forthe manufacture of PCBs that provide level copper deposits whilebolstering the throwing power of the bath.

SUMMARY OF THE INVENTION

A reaction product of one or more diamines including primary orsecondary amine moieties and one or more compounds having formula:

where R is a linking group.

Compositions include one or more sources of metal ions, an electrolyteand a reaction product of one or more diamines including primary orsecondary amine moieties and one or more compounds having formula:

where R is a linking group.

Methods include providing a substrate; providing a composition includingone or more sources of metal ions, an electrolyte and one or morereaction products of one or more diamines including primary or secondaryamine moieties and one or more compounds having formula:

where R is a linking group; contacting the substrate with thecomposition; applying a current to the substrate; and plating a metal onthe substrate.

The electroplating baths which include the reaction products providesubstantially level metal layers across a substrate, even on substrateshaving small features and on substrates having a variety of featuresizes. The metal plating compositions have good throwing power andeffectively deposit metals in blind vias and through-holes.

DETAILED DESCRIPTION OF THE INVENTION

As used throughout this specification the following abbreviations shallhave the following meanings unless the context clearly indicatesotherwise: A=amperes; A/dm²=amperes per square decimeter=ASD; °C.=degrees Centigrade; g=gram; mg=milligram; ppm=parts per million=mg/L;mol=moles; L=liter, μm=micron=micrometer; mm=millimeters;cm=centimeters; PO=propyleneoxide; EO=ethyleneoxide; DI=deionized;mL=milliliter; Mw=weight average molecular weight; and Mn=number averagemolecular weight; and v/v=volume to volume. All numerical ranges areinclusive and combinable in any order, except where it is clear thatsuch numerical ranges are constrained to add up to 100%.

As used throughout the specification, “feature” refers to the geometrieson a substrate. “Aperture” refers to recessed features includingthrough-holes and blind vias. As used throughout this specification, theterm “plating” refers to metal electroplating. “Deposition” and“plating” are used interchangeably throughout this specification.“Halide” refers to fluoride, chloride, bromide and iodide. “Accelerator”refers to an organic additive that increases the plating rate of theelectroplating bath and such accelerators may also function asbrighteners. “Suppressor” refers to an organic additive that suppressesthe plating rate of a metal during electroplating. “Leveler” refers toan organic compound that is capable of providing a substantially levelor planar metal layer. The terms “leveler” and “leveling agent” are usedinterchangeably throughout this specification. The terms “printedcircuit boards” and “printed wiring boards” are used interchangeablythroughout this specification. The term “moiety” means a part of amolecule or polymer that may include either whole functional groups orparts of functional groups as substructures. The terms “moiety” and“group” are used interchangeably throughout the specification. Theindefinite articles “a” and “an” refer to the singular and the plural.

Compounds are reaction products of one or more diamines includingprimary or secondary amine moieties and one or more compounds havingformula:

where R is a linking group joined by covalent bonds to the nitrogen ofthe anhydride rings. Such linking groups are organic moieties.Preferably R has the following structures:

where R₁ and R₂ may be the same or different and include hydrogen,linear or branched (C₁-C₄)alkyl, hydroxyl, hydroxy(C₁-C₃)alkyl,carboxyl, carboxy(C₁-C₃)alkyl and (C₁-C₃)alkoxy, preferably, R₁ and R₂include hydrogen or linear or branched (C₁-C₄)alkyl, more preferably, R₁and R₂ are hydrogen and m is an integer of 1 to 15, preferably from 2 to10, more preferably from 2 to 3;

where R₁ and R₂ are defined as above; R₃ and R₄ may be the same ordifferent and are the same groups as R₁ and R₂; R₅ and R₆ may be thesame or different and include hydrogen, carboxyl andcarboxy(C₁-C₃)alkyl, preferably R₅ and R₆ may be the same or differentand are hydrogen and carboxyl; and m is as defined above and n is aninteger of 1 to 15, preferably from 2 to 10, more preferably from 2 to 3and preferably m and n are the same;

where R₇, R₈, R₉ and R₁₀ may be the same or different and includehydrogen, linear or branched (C₁-C₅)alkyl, linear or branchedhydroxy(C₁-C₅)alkyl, carboxy(C₁-C₃)alkyl, linear or branched(C₁-C₅)alkoxy, preferably R₇, R₈, R₉ and R₁₀ may be the same ordifferent and are hydrogen, linear or branched (C₁-C₅)alkyl, morepreferably R₇, R₈, R₉ and R₁₀ are hydrogen; q, r and t may be the sameor different and are integers of 1 to 10, preferably from 2 to 3; and

where R₁₁ and R₁₂ may be the same or different and are hydrogen orlinear or branched (C₁-C₅)alkyl, preferably R₁₁ and R₁₂ are hydrogen, Aris an aryl group having 5 to 6 carbon atoms, preferably 6 carbon atoms,more preferably R of formula (V) has the following structure:

and n is as defined above.

Diamines include compounds having a general formula:

where R′ is a linking group joined by covalent bonds to the terminalnitrogens. Such linking groups are organic moieties. Preferably R′ hasthe following structures:

a substituted or unsubstituted (C₆-C₁₈)aryl;

where R₁₃ and R₁₄ may be the same or different and include hydrogen,linear or branched (C₁-C₁₂)alkyl, alkyleneoxy or substituted orunsubstituted (C₆-C₁₈)aryl. Substituents on the aryl groups include, butare not limited to linear or branched (C₁-C₁₂)alkyl, linear or branchedhydroxy(C₁-C₁₂)alkyl, hydroxyl, carboxyl, linear or branchedcarboxy(C₁-C₁₂)alkyl, nitro group, mercapto group, linear or branchedmercapto(C₁-C₁₂)alkyl, linear or branched halo(C₁-C₁₂)alkyl, preferablythe aryl is a six membered ring, more preferably the aryl is anunsubstituted six membered ring; variables p and s may be the same ordifferent and are independently integers of one or greater, preferablyfrom 1 to 10, variable e is an integer of 0 to 3, preferably from 1 to2, more preferably e is 1 and variables a, b, c and d may be the same ordifferent and are numbers from 1 or greater, preferably from 1 to 10;when R₁₃ and R₁₄ are alkyleneoxy, the terminal carbons of thealkyleneoxy groups may be taken together to form a ring with the provisothat when R₁₃ and R₁₄ are joined together to form the ring, R′ is alsoan alkyleneoxy group; R₁₅-R₂₂ may be the same or different and includehydrogen, linear or branched (C₁-C₅)alkyl, linear or branchedhydroxy(C₁-C₅)alkyl or linear or branched (C₁-C₅)alkoxy; and Z may be acarbon atom or nitrogen atom.

Diamines also include, but are not limited to, heterocyclic saturatednon-aromatic compounds having the following formula:

where R₂₃ and R₂₄ may be the same or different and are hydrogen oramino(C₁-C₁₀)alkyl, preferably R₂₃ and R₂₄ are hydrogen oramino(C₁-C₃)alkyl.

In general, the reaction products are prepared by mixing one or morebisanhydride compounds in an organic solvent, such as dimethylformamide(DMF), with stiffing and heating or with stiffing at room temperature.One or more diamines are then added dropwise to the mixture with heatingand stiffing. Heating is typically done in a range of 50° C. to 150° C.This mixture may then be heated for 2 hours to 15 hours followed bybringing the temperature down to room temperature with stiffing. Theproduct may be precipitated by adding anhydrous ethanol. The amounts ofreactants may vary but in general sufficient amount of each reactant isadded to provide a product where the molar ratio of the bisanhydridereactant to the amine reactant ranges from 1:0.1 to 1:2, preferably1:0.5 to 1:2.

The reaction products may be polymers having inner salts such as thosehaving a formula:

where R and R′ are as defined above and the variable v is 2 or greater.Preferably v is 2 to 200.

The plating composition and method are useful in providing asubstantially level plated metal layer on a substrate, such as a printedcircuit board. Also, the plating composition and method are useful infilling apertures in a substrate with metal. Also, the metal depositshave good throwing power.

Any substrate upon which metal can be electroplated is useful in thepresent invention. Such substrates include, but are not limited to:printed wiring boards, integrated circuits, semiconductor packages, leadframes and interconnects. An integrated circuit substrate may be a waferused in a dual damascene manufacturing process. Such substratestypically contain a number of features, particularly apertures, having avariety of sizes. Through-holes in a PCB may have a variety ofdiameters, such as from 50 μm to 2 mm in diameter. Such through-holesmay vary in depth, such as from 35 μm to 15 mm or greater. PCBs maycontain blind vias having a wide variety of sizes, such as up to 200 μmdiameter and 150 μm depth.

The metal plating compositions contain a source of metal ions, anelectrolyte, and a leveling agent, where the leveling agent is areaction product as described above. The metal plating compositions maycontain a source of halide ions, an accelerator and a suppressor. Metalswhich may be electroplated from the compositions include, but are notlimited to: copper, tin and tin/copper alloys.

Suitable copper ion sources are copper salts and include withoutlimitation: copper sulfate; copper halides such as copper chloride;copper acetate; copper nitrate; copper tetrafluoroborate; copperalkylsulfonates; copper arylsulfonates; copper sulfamate; copperperchlorate and copper gluconate. Exemplary copper alkylsulfonatesinclude copper (C₁-C₆)alkylsulfonate and more preferably copper(C₁-C₃)alkylsulfonate. Preferred copper alkylsulfonates are coppermethanesulfonate, copper ethanesulfonate and copper propanesulfonate.Exemplary copper arylsulfonates include, without limitation, copperbenzenesulfonate and copper p-toluene sulfonate. Mixtures of copper ionsources may be used. One or more salts of metal ions other than copperions may be added to the present electroplating baths. Typically, thecopper salt is present in an amount sufficient to provide an amount ofcopper metal of 10 to 400 g/L of plating solution.

Suitable tin compounds include, but are not limited to salts, such astin halides, tin sulfates, tin alkane sulfonate such as tin methanesulfonate, tin aryl sulfonate such as tin benzenesulfonate and tintoluene sulfonate. The amount of tin compound in these electrolytecompositions is typically an amount that provides a tin content in therange of 5 to 150 g/L. Mixtures of tin compounds may be used in anamount as described above.

The electrolyte useful in the present invention may be alkaline oracidic. Typically the electrolyte is acidic. Suitable acidicelectrolytes include, but are not limited to: sulfuric acid, aceticacid, fluoroboric acid, alkanesulfonic acids such as methanesulfonicacid, ethanesulfonic acid, propanesulfonic acid and trifluoromethanesulfonic acid, arylsulfonic acids such as benzenesulfonic acid andp-toluene sulfonic acid, sulfamic acid, hydrochloric acid, hydrobromicacid, perchloric acid, nitric acid, chromic acid and phosphoric acid.Mixtures of acids may be advantageously used in the present metalplating baths. Preferred acids include sulfuric acid, methanesulfonicacid, ethanesulfonic acid, propanesulfonic acid, hydrochloric acid andmixtures thereof. The acids may be present in an amount in the range offrom 1 to 400 g/L. Electrolytes are generally commercially availablefrom a variety of sources and may be used without further purification.

Such electrolytes may optionally contain a source of halide ions.Typically chloride ions are used. Exemplary chloride ion sources includecopper chloride, tin chloride, sodium chloride and hydrochloric acid. Awide range of halide ion concentrations may be used in the presentinvention. Typically, the halide ion concentration is in the range offrom 0 to 100 ppm based on the plating bath. Such halide ion sources aregenerally commercially available and may be used without furtherpurification.

The plating compositions preferably contain an accelerator. Anyaccelerators (also referred to as brightening agents) are suitable foruse in the present invention. Such accelerators are well-known to thoseskilled in the art. Accelerators include, but are not limited to,N,N-dimethyl-dithiocarbamic acid-(3-sulfopropyl)ester;3-mercapto-propylsulfonic acid-(3-sulfopropyl)ester;3-mercapto-propylsulfonic acid sodium salt; carbonicacid-dithio-o-ethylester-s-ester with 3-mercapto-1-propane sulfonic acidpotassium salt; bis-sulfopropyl disulfide; bis-(sodiumsulfopropyl)-disulfide; 3-(benzothiazolyl-s-thio)propyl sulfonic acidsodium salt; pyridinium propyl sulfobetaine;1-sodium-3-mercaptopropane-1-sulfonate; N,N-di methyl-dithiocarbamicacid-(3-sulfoethyl)ester; 3-mercapto-ethyl propylsulfonicacid-(3-sulfoethyl)ester; 3-mercapto-ethylsulfonic acid sodium salt;carbonic acid-dithio-o-ethylester-s-ester with 3-mercapto-1-ethanesulfonic acid potassium salt; bis-sulfoethyl disulfide;3-(benzothiazolyl-s-thio)ethyl sulfonic acid sodium salt; pyridiniumethyl sulfobetaine; and 1-sodium-3-mercaptoethane-1-sulfonate.Accelerators may be used in a variety of amounts. In general,accelerators are used in an amount of 0.1 ppm to 1000 ppm. Preferably,the accelerator concentration is in the range of 0.5 ppm to 100 ppm.More preferably, the accelerator concentration is in the range of 0.5ppm to 50 ppm, and most preferably, in the range of 0.5 ppm to 25 ppm.

Any compound capable of suppressing the metal plating rate may be usedas a suppressor in the present electroplating compositions. Suitablesuppressors include, but are not limited to, polypropylene glycolcopolymers and polyethylene glycol copolymers, including ethyleneoxide-propylene oxide (“EO/PO”) copolymers and butyl alcohol-ethyleneoxide-propylene oxide copolymers. Suitable butyl alcohol-ethyleneoxide-propylene oxide copolymers are those having a weight averagemolecular weight of 100 to 100,000, preferably 500 to 10,000. When suchsuppressors are used, they are typically present in an amount in therange of from 1 to 10,000 ppm based on the weight of the composition,and more typically from 5 to 10,000 ppm.

In general, the reaction products have a number average molecular weight(Mn) of 200 to 10,000, typically from 300 to 50,000, preferably from 500to 8000, although reaction products having other Mn values may be used.Such reaction products may have a weight average molecular weight (Mw)value in the range of 1000 to 50,000, typically from 5000 to 30,000,although other Mw values may be used.

The amount of the reaction product (leveling agent) used in the metalelectroplating compositions depends upon the particular leveling agentsselected, the concentration of the metal ions in the electroplatingcomposition, the particular electrolyte used, the concentration of theelectrolyte and the current density applied. In general, the totalamount of the leveling agent in the electroplating composition rangesfrom 0.01 ppm to 5,000 ppm based on the total weight of the platingcomposition, although greater or lesser amounts may be used. Preferably,the total amount of the leveling agent is from 0.1 to 1000 ppm, morepreferably, from 0.1 to 500 ppm, most preferably, from 0.1 to 100 ppm.In addition to their leveling activity, the reaction products may alsofunction as suppressors.

The electroplating compositions may be prepared by combining thecomponents in any order. It is preferred that the inorganic componentssuch as source of metal ions, water, electrolyte and optional halide ionsource are first added to the bath vessel followed by the organiccomponents such as leveling agent, accelerator, suppressor, and anyother organic component.

The electroplating compositions may optionally contain two or moreleveling agents. Such additional leveling agents may be another levelingagent of the present invention, or alternatively, may be anyconventional leveling agent. Suitable conventional leveling agents thatcan be used in combination with the present leveling agents include,without limitations, those disclosed in U.S. Pat. No. 6,610,192 to Stepet al., U.S. Pat. No. 7,128,822 to Wang et al., U.S. Pat. No. 7,374,652to Hayashi et al. and U.S. Pat. No. 6,800,188 to Hagiwara et al. Suchcombination of leveling agents may be used to tailor the characteristicsof the plating bath, including leveling ability and throwing power.

Typically, the plating compositions may be used at any temperature from10 to 65° C. or higher. Preferably, the temperature of the platingcomposition is from 10 to 35° C. and more preferably, from 15 to 30° C.

In general, the metal electroplating compositions are agitated duringuse. Any suitable agitation method may be used and such methods arewell-known in the art. Suitable agitation methods include, but are notlimited to air sparging, work piece agitation, and impingement.

Typically, a substrate is electroplated by contacting the substrate withthe plating composition. The substrate typically functions as thecathode. The plating composition contains an anode, which may be solubleor insoluble. Potential is typically applied to the electrodes.Sufficient current density is applied and plating performed for a periodof time sufficient to deposit a metal layer having a desired thicknesson the substrate as well as fill blind vias, trenches and through-holesor to conformally plate through-holes. Current densities include, butare not limited to, the range of 0.05 to 10 A/dm², although higher andlower current densities may be used. The specific current densitydepends in part upon the substrate to be plated, the composition of theplating bath and the desired surface metal thickness. Such currentdensity choice is within the abilities of those skilled in the art.

An advantage of the present invention is that substantially level metaldeposits may be obtained on a PCB and other substrates. By“substantially level” metal layer is meant that the step height, i.e.,the difference between areas of dense very small apertures and areasfree of or substantially free of apertures, is less than 5 μm, andpreferably, less than 1 μm. Through-holes and/or blind vias in the PCBare substantially filled. A further advantage of the present inventionis that a wide range of apertures and aperture sizes may be filled.

Throwing power is defined as the ratio of the average thickness of themetal plated in the center of a through-hole compared to the averagethickness of the metal plated at the surface of the PCB sample and isreported as a percentage. The higher the throwing power, the better theplating composition is able to conformally plate the through-hole.

The compounds provide metal layers having a substantially level surfaceacross a substrate, even on substrates having small features and onsubstrates having a variety of feature sizes. The plating methodseffectively deposit metals in through-holes and blind via holes suchthat the metal plating compositions have good throwing power and reducedcracking.

While the methods of the present invention have been generally describedwith reference to printed circuit board manufacture, it is appreciatedthat the present invention may be useful in any electrolytic processwhere an essentially level or planar metal deposit and filled orconformally plated apertures are desired. Such processes include, butare not limited to semiconductor packaging and interconnect manufactureas well as plating on plastics.

The following examples are intended to further illustrate the inventionbut are not intended to limit its scope.

Example 1

Ethylenediaminetetraacetic (EDTA) bisanhydride (10 mmoles) was dissolvedin 30 mL dimethylformamide (DMF) and 10 mmoles of hexamethylenediamine(structure A) was dissolved in 30 mL of DMF. The EDTA bisanhydridesolution was added into the hexamethylenediamine solution dropwise. Themixture was stirred at 60° C. for 12 hours under a nitrogen atmosphere.The reaction product was precipitated by adding 60 mL of anhydrousethanol, then washed by acetone and dried under a vacuum. The reactionproduct included an inner salt as shown by structure (B).

The variable v is as defined above.

Example 2

EDTA bisanhydride (10 mmoles) was dissolved in 30 mL dimethylformamide(DMF) and 10 mmoles of the diamine shown below (structure C) wasdissolved in 30 mL of DMF. The EDTA bisanhydride solution was added intothe diamine solution dropwise. The mixture was stirred at 60° C. for 12hours under a nitrogen atmosphere. The reaction product was precipitatedby adding 60 mL of anhydrous ethanol, then washed by acetone and driedunder a vacuum. The reaction product included an inner salt as shown bystructure (D).

The variable v is as defined above.

Example 3

EDTA bisanhydride (10 mmoles) was dissolved in 30 mL dimethylformamide(DMF) and 10 mmoles of the diamine shown below (structure E) wasdissolved in 30 mL of DMF. The EDTA bisanhydride solution was added intothe diamine solution dropwise. The mixture was stirred at 60° C. for 12hours under a nitrogen atmosphere. The reaction product was precipitatedby adding 60 mL of anhydrous ethanol, then washed by acetone and driedunder a vacuum. The reaction product included an inner salt as shown bystructure (F).

The variable v is as defined above.

Example 4

EDTA bisanhydride (10 mmoles) was dissolved in 30 mL dimethylformamide(DMF) and 10 mmoles of the diamine shown below (structure G) wasdissolved in 30 mL of DMF. The EDTA bisanhydride solution was added intothe diamine solution dropwise. The mixture was stirred at 60° C. for 12hours under a nitrogen atmosphere. The reaction product was precipitatedby adding 60 mL of anhydrous ethanol, then washed by acetone and driedunder a vacuum. The reaction product included an inner salt as shown bystructure (H).

The variable v is as defined above.

Example 5

EDTA bisanhydride (10 mmoles) was dissolved in 30 mL dimethylformamide(DMF) and 10 mmoles of the diamine shown below (structure I) wasdissolved in 30 mL of DMF. The EDTA bisanhydride solution was added intothe diamine solution dropwise. The mixture was stirred at 60° C. for 12hours under a nitrogen atmosphere. The product was obtained byevaporating DMF under reduced pressure. The reaction product included aninner salt as shown by structure (J).

The variable v is as defined above.

Example 6

EDTA bisanhydride (10 mmoles) was dissolved in 30 mL dimethylformamide(DMF) and 10 mmoles of the diamine shown below (structure K) wasdissolved in 30 mL of DMF. The EDTA bisanhydride solution was added intothe diamine solution dropwise. The mixture was stirred at 60° C. for 12hours under a nitrogen atmosphere. The product was obtained byevaporating DMF under reduced pressure. The reaction product included aninner salt as shown by structure (L).

The variable v is as defined above.

Example 7

EDTA bisanhydride (10 mmoles) was dissolved in 30 mL dimethylformamide(DMF) and 10 mmoles of the diamine shown below (structure M) wasdissolved in 30 mL of DMF. The EDTA bisanhydride solution was added intothe diamine solution dropwise. The mixture was stirred at 60° C. for 12hours under a nitrogen atmosphere. The product was obtained byevaporating DMF under reduced pressure. The reaction product included aninner salt as shown by structure (N).

where x=2.5.

The variable v is as defined above and “x” is as defined above.

Example 8

EDTA bisanhydride (10 mmoles) was dissolved in 30 mL dimethylformamide(DMF) and 10 mmoles of the diamine shown below (structure O) wasdissolved in 30 mL of DMF. The EDTA bisanhydride solution was added intothe diamine solution dropwise. The mixture was stirred at 60° C. for 12hours under a nitrogen atmosphere. The reaction product was obtained byevaporating DMF under reduced pressure. The reaction product included aninner salt as shown by structure (P).

where y=12.5 and x+z=6 where x=2.5 and z=3.5.

The variables v is as defined above and “x”, “y”, and “z” are as definedabove.

Example 9

Eighteen aqueous acid copper electroplating baths having the basicformulation disclosed in Table 1 below were prepared.

TABLE 1 COMPONENT AMOUNT Purified copper sulfate pentahydrate 73 g/LSulfuric acid 235 g/L Chloride ions as hydrogen chloride 60 ppm EO/POcopolymer with a molecular weight of 1.5 g/L <5000 and terminal hydroxylgroupsThe pH of the baths was less than 1. The baths differed by the amount ofreaction product (leveler) and brightener included in the baths. Thebrightener was bis(sodium-sulfopropyl)disulfide. The amount and type ofleveler and brightener included in each bath is disclosed in Table 2below.

Test panels 3.2 mm thick with average through-hole diameters of 300 μmwere immersed in the aqueous acid copper electroplating baths. Copperplating was done for 80 minutes at 25° C. The current density was 2.16ASD. The copper plated samples were analyzed to determine the throwingpower (“TP”) of the plating bath, and percent cracking according to thefollowing methods.

Throwing power was calculated by determining the ratio of the averagethickness of the metal plated in the center of a through-hole comparedto the average thickness of the metal plated at the surface of the testpanel. The throwing power is reported in Table 2 as a percentage.

Cracking was determined according to the industry standard procedure,IPC-TM-650-2.6.8. Thermal Stress, Plated-Through Holes, published by IPC(Northbrook, Ill., USA), dated May, 2004, revision E. Each plated panelwas solder floated at 288° C. six times to determine the panelsresistance to cracking. If no cracking was observed, the panel passedthe thermal stress test. If any cracking was observed, the panel failedthe test. The results for the throwing power test and the thermal stresstest are disclosed in Table 2.

TABLE 2 EXAMPLE LEVELER BRIGHTENER THERMAL (LEVELER) (ppm) (ppm) TP %STRESS TEST Example 1 10 3 78 No Example 1 10 8 77 No Example 2 10 10 96No Example 2 1 10 83 Pass Example 2 1 5 110 No Example 3 1 10 80 NoExample 3 1 5 105 No Example 3 10 3 78 No Example 3 10 8 77 No Example 43 10 63 Pass Example 4 1 10 73 No Example 5 3 10 64 Pass Example 6 3 1072 Pass Example 6 1 10 108 No Example 7 3 10 57 Pass Example 7 1 10 50Pass Example 8 3 10 58 Pass Example 8 1 10 51 Pass

Although the quality of the solder float test varied for the panels, theTP % ranged from good to very good. A TP of greater than 100% indicatedthat the copper thickness inside the hole was higher than on thesurface. A TP of greater than 100% also indicated that the levelershowed strong polarization.

The invention claimed is:
 1. A method comprising: a) contacting asubstrate to be metal plated with a composition comprising: one or moresources of metal ions, wherein the one or more sources of metal ions arechosen from copper salts and tin salts, an electrolyte and a reactionproduct of one or more reaction products of one or more diamines,wherein the one or more diamines has a formula:

wherein R′ is a linking group and R₁₃ and R₁₄ may be the same ordifferent and comprise hydrogen, linear or branched (C₁-C₁₂)alkyl,alkyleneoxy or substituted or unsubstituted (C₆-C₁₈)aryl, wherein R′ hasa moiety:

a substituted or unsubstituted (C₆-C₁₈)aryl; R₁₅-R₂₂ may be the same ordifferent and comprise hydrogen, linear or branched (C₁-C₅)alkyl, linearor branched hydroxy(C₁-C₅)alkyl or linear or branched (C₁-C₅)alkoxy, andZ is a carbon atom or nitrogen atom; and p and s may be the same ordifferent and are independently integers of one or greater, e is aninteger of 0 to 3, and a, b, c and d may be the same or different andare numbers from 1 or greater; or wherein the one or more diamines has aformula:

wherein R₂₃ and R₂₄ may be the same or different and are hydrogen oramino(C₁-C₁₀)alkyl, preferably R₂₃ and R₂₄ are hydrogen oramino(C₁-C₃)alkyl, and one or more compounds having formula:

wherein R is a linking group having a moiety:

wherein R₁, R₂, R₃ and R₄ may be the same or different and comprisehydrogen, linear or branched (C₁-C₄)alkyl, hydroxyl,hydroxy(C₁-C₃)alkyl, carboxyl, carboxy(C₁-C₃)alkyl or (C₁-C₃)alkoxy, R₅and R₆ may be the same or different and comprise hydrogen, carboxyl andcarboxy(C₁-C₃)alkyl, R₇, R₈, R₉ and R₁₀ may be the same or different andcomprise hydrogen, linear or branched (C₁-C₅)alkyl, linear or branchedhydroxy(C₁-C₅)alkyl, carboxy(C₁-C₃)alkyl, linear orbranched(C₁-C₅)alkoxy, R₁₁ and R₁₂ may be the same or different andcomprise hydrogen or linear or branched (C₁-C₅)alkyl, Ar is an arylgroup having 5 to 6 carbon atoms; n and m may be the same or differentand are integers of 1 to 15; and q, r and t may be the same or differentare integers of 1 to 10; b) contacting the substrate with thecomposition; c) applying a current to the substrate; and d) platingcopper, tin or tin-copper alloy on the substrate.
 2. The method of claim1, wherein the substrate comprises a plurality of through-holes andvias.